opp is 28/24
i 3bet because he's pretty loose.
Lookin back i think a fold on the flop or call down if i call the flop.
BUT i was just struggling to put him on a hand. I'm basically putting him on a flush i doubt he could play 3's t's 4's JJ+ like this. (perhaps QQ with Qd)
thoughts?

I don't like your preflop 3bet though. I think KTo is too weak OOP vs MP. Yes, he could be loose but KTo plays so badly OOP you rarely make money unless he folds preflop often or to cbets. Given that you are deep he should call very very often preflop.

On the flop, I usually consider checking. I don't think I miss value because he is not stacking off by calling down worse than KT imo. Since I can't bet/bet/shove for value I usually want 2 streets of value. If I bet flop, I can't get max 2 streets. In some cases, you can bet/bet/check/call or bet flop, check/shove turn but seems a bit ambitious without some reads. If I check flop, I check/call easily. I don't miss value because FDs bet. I might miss some value vs some midpairs but they won't call down anyway, I get value later. I also get value against some bluffs that would just fold to the cbet.

I do think that the biggest problem is the preflop 3bet hand selection. KTo seems like a bad choice imo. More suited hands FTW in 3bet pots!